Patent EP0194148A2 successfully refreshed from Google Patents.
EP0194148A2
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EP
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Method and apparatus for detecting coloured regions, and method and apparatus for sorting articles thereby
Assignee: Lockwood Graders UK Ltd
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Filing: 1986-03-06
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Granted: —
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Expires: 2006-03-06
Abstract
Abstract A method of colour detection, in which electrical signals derived from two quantities, preferably orthogonal quantities, for example (R-L) and (B-L) are digitised. A time-shift is applied to the signals, either before or after digitisation, and a difference signal is formed between each original signal, and its time-shifted counterpart. The difference signals are then used as a key to a «lookup» table, to provide an output only when specified combinations of the two difference signals are encountered.
Inventors
- 👤 Timothy James Dennis
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-29 21:24
CPC Classifications
G; G06; G06T; G06T7/00; G06T7/0002; G06T7/0004; G06T7/0008; B; B07; B07C; B07C5/00; B07C5/34; B07C5/342; B07C5/3422; G06T7/90; G06T2207/00; G06T2207/10; G06T2207/10016; G06T2207/10024; G06T2207/30; G06T2207/30108; G06T2207/30128
Claims Analysis
Total Claims: 23
Claim 1
Independent Claim
145 words
A method of detecting a region of an image having a particular colour, which method comprises scanning the image using a raster-scan technique, to obtain therefrom electrical signals indicative of at least a pair of quantities relating to successive pixels on the raster-scan, the said pair of quantities together containing information relating to both hue and colour saturation, applying at least one time shift to each of the said signals and.obtaining a spatial difference signal by differencing each of the said signals and a time-shifted counterpart thereof, the spatial difference signals being indicative of spatial variation of the corresponding electrical colour signal in the image, and applying the said spatial difference signals as an index to a memory device having a plurality of storage locations serving as a look-up table, and adapted to provide an output only for specific combinations of the said difference signals.
Claim 2
Independent Claim
145 words
A method of detecting a region of an image having a particular colour, which method comprises scanning the image using a raster-scan technique, to obtain therefrom electrical signals indicative of at least a pair of quantities relating to successive pixels on the raster-scan, the said pair of quantities together containing information relating to both hue and colour saturation, applying at least one time shift to each of the said signals and.obtaining a spatial difference signal by differencing each of the said signals and a time-shifted counterpart thereof, the spatial difference signals being indicative of spatial variation of the corresponding electrical colour signal in the image, and applying the said spatial difference signals as an index to a memory device having a plurality of storage locations serving as a look-up table, and adapted to provide an output only for specific combinations of the said difference signals.
Claim 3
Dependent Claim
25 words
A method as claimed in Claim 1, wherein the said electrical signals are mutually orthogonal components of a three-colour television signal or the logarithms thereof.
Claim 4
Dependent Claim
31 words
A method as claimed in Claim 1, wherein the said electrical signals include at least two of the red, green, and blue signals from a television camera or the logarithms thereof.
Claim 5
Dependent Claim
33 words
A method as claimed in Claim 1, wherein the said electrical signals are (Red-Luminance) and (Blue-Luminance), wherein luminance is defined as (0.3 Red + 0.59 Green + 0.11 Blue), or the logarithms thereof.
Claim 6
Independent Claim
30 words
A method as claimed in any one of Claims 1 to 6, wherein the three spatial difference signals are each applied as a separate index to a three-dimensional look-up table.
Claim 7
Independent Claim
56 words
A method as claimed in any one of Claims 1 to 6, wherein three spatial difference signals are applied in three pair combinations as indices to at least two separate two-dimensional look-up tables, and outputs from the said look-up tables are combined to provide the said output for specific combinations of the said spatial difference signals.
Claim 8
Independent Claim
54 words
A method as claimed in any one of Claims 1 to 6, wherein each of the difference signals is used individually as an index to a 1-dimensional look-up table, and outputs from each of the said 1-dimensional look-up tables are combined to provide the said output for specific combinations of the said difference signals.
Claim 9
Independent Claim
19 words
A method as claimed in any one of the preceding claims wherein the electronic memory locations are multi-bit locations.
Claim 10
Independent Claim
60 words
A method as claimed in any one of the preceding claims including the step of generating data for the said lookup table by scanning a datum image including the said colour and storing values in appropriate ones of the storage locations dependant upon the frequency of occurrence in the datum image of the corresponding combination of spatial colour difference signals.
Claim 11
Independent Claim
261 words
A method of determining which of a plurality of articles include a coloured region of a particular type, which method comprises scanning a target image having a region of the said type using a raster-scan technique, to obtain therefrom electrical signals indicative of at least a pair of quantities relating to successive pixels on the raster-scan, the said pair of quantities together containing information relating to both dominant wavelength and spectral purity, obtaining digital values corresponding to the said electrical signals, and applying the said digital values as an index to a memory device having a plurity of storage locations serving as α-look-up table, and adapted to provide an output only for specific combinations of the said digital values, and thereby determining the locations of the look-up table corresponding to the target colour, labelling further storage locations of the look-up table as corresponding to the target colour, the said further storage locations being in regions of the look-up table corresponding to substantially the same dominant wavelength as the said region, but differing luminance and/or spectral purity, and thereby effecting calibration of the look-up table, causing the articles to pass through an inspection region, scanning the articles in the inspection region using the same raster-scan technique, and thereby obtaining corresponding electrical signals from the image of the said articles, deriving corresponding digital values from the said electrical signals, and applying the said digital values as indices to the said memory device, and thereby generating an output for every occurrence on one of the articles of a colour within the aforesaid larger region.
Claim 12
Independent Claim
261 words
A method of determining which of a plurality of articles include a coloured region of a particular type, which method comprises scanning a target image having a region of the said type using a raster-scan technique, to obtain therefrom electrical signals indicative of at least a pair of quantities relating to successive pixels on the raster-scan, the said pair of quantities together containing information relating to both dominant wavelength and spectral purity, obtaining digital values corresponding to the said electrical signals, and applying the said digital values as an index to a memory device having a plurity of storage locations serving as α-look-up table, and adapted to provide an output only for specific combinations of the said digital values, and thereby determining the locations of the look-up table corresponding to the target colour, labelling further storage locations of the look-up table as corresponding to the target colour, the said further storage locations being in regions of the look-up table corresponding to substantially the same dominant wavelength as the said region, but differing luminance and/or spectral purity, and thereby effecting calibration of the look-up table, causing the articles to pass through an inspection region, scanning the articles in the inspection region using the same raster-scan technique, and thereby obtaining corresponding electrical signals from the image of the said articles, deriving corresponding digital values from the said electrical signals, and applying the said digital values as indices to the said memory device, and thereby generating an output for every occurrence on one of the articles of a colour within the aforesaid larger region.
Claim 13
Dependent Claim
33 words
A method of detecting colour defects in articles, which method comprises forming a colour image of the articles, and detecting coloured regions in the image by a method as claimed in Claim 1.
Claim 14
Dependent Claim
49 words
A method of sorting articles, which method comprises passing the articles through an inspection region, detecting colour defects in the articles in the inspection region by a method as claimed in Claim 11, and routing the articles differently according to the presence or absence in them of colour defects.
Claim 15
Dependent Claim
189 words
Apparatus for detecting a coloured region of an object, which apparatus comprises a colour television camera for viewing the object, means for deriving from the colour television camera electrical output signals at least a pair of signals together containing information relating to both hue and colour saturation, means for applying at least one time shift to each of the said electrical signals, and for obtaining from each of the signals a spatial difference signal between each of the signals and its time-shifted counterpart, means for generating at least a pair of digital values corresponding to the values of spatial difference signals, an electronic memory device having a plurality of storage locations provided with corresponding address lines to allow the selection of respective ones of said memory locations, means for applying the said digital values as address signals to the said address lines thereby to identify each storage location as being associated with a particular combination of the said spatial difference signals, and means for reading from the memory locations a value which is dependent upon whether or not the colour television camera is viewing a particular chosen colour transition.
Claim 16
Dependent Claim
189 words
Apparatus for detecting a coloured region of an object, which apparatus comprises a colour television camera for viewing the object, means for deriving from the colour television camera electrical output signals at least a pair of signals together containing information relating to both hue and colour saturation, means for applying at least one time shift to each of the said electrical signals, and for obtaining from each of the signals a spatial difference signal between each of the signals and its time-shifted counterpart, means for generating at least a pair of digital values corresponding to the values of spatial difference signals, an electronic memory device having a plurality of storage locations provided with corresponding address lines to allow the selection of respective ones of said memory locations, means for applying the said digital values as address signals to the said address lines thereby to identify each storage location as being associated with a particular combination of the said spatial difference signals, and means for reading from the memory locations a value which is dependent upon whether or not the colour television camera is viewing a particular chosen colour transition.
Claim 17
Dependent Claim
20 words
Apparatus as claimed in Claim 13, wherein the said electrical signals are mutually orthogonal components of a three-colour television signal.
Claim 18
Dependent Claim
26 words
Apparatus as claimed in Claim 14, wherein the said electrical signals include at least two of the red, green, and blue signals from a television camera.
Claim 19
Dependent Claim
28 words
Apparatus as claimed in Claim 14, wherein the said electrical signals are (Red-Luminance) and (Blue-Luminance), wherein luminance is defined as (0.3 Red + 0.59 Green + 0.11 Blue).
Claim 20
Dependent Claim
30 words
Apparatus as claimed in any one of Claims 13 to 16, including means for deriving generating the said signals as logarithms of corresponding signals derived from the colour television camera.
Claim 21
Dependent Claim
39 words
Apparatus as claimed in any one of Claims 13 to 17, wherein the electronic memory is arranged as a three- dimensional look-up table, as two or more separate two-dimensional look-up tables, or as two or more 1-dimensional look-up tables.
Claim 22
Dependent Claim
19 words
Apparatus as claimed in any one of Claims 13 to 18, wherein the electronic memory locations are multi-bit locations.
Claim 23
Dependent Claim
64 words
Apparatus for sorting articles, comprising means for conveying the articles through an inspection region, apparatus as claimed in any one of Claims 13 to 19 for detecting coloured regions on the articles, the said colour television camera being arranged to continuously scan the articles in the said region, and means for routing the said articles in accordance with coloured regions detected on the articles.
References Cited (Backward Citations)
No citation records indexed.
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